Sigh. It's a compilation movie that gamers make showing off their online gaming skills. Many people edited complicated videos of such game-play, which often contains exciting music. Now normally, those would just be any old song they want to use. But those videos have gotten so big some of them, that gamers have to use original music.

I hope this anwers many questions.

And NO, I don't play the games, I just happen to know one gamer who does just this kind of video.